Undulators are magnetic assembly insertion devices that are used at synchrotron radiation sources such as Free Electron Lasers (FEL) and Storage Rings. Undulators are used in the medical and industrial markets for x-ray or longer wavelength photon beam purposes.
Specifically, undulators include opposing magnet arrays producing a periodic spatial magnetic field distribution in a gap between them. A high-energy electron beam passing through this gap parallel to the arrays “wiggles” back and forth in its trajectory due to the periodic magnetic field. Undulators further may include temperature-stabilizing components selectively arranged to prevent a temperature-dependent change in the magnetic field of the undulator.
Undulators are periodic magnetic structures, and their magnetic field is essentially sinusoidal. Undulators with a magnetic field in one plane are called linearly polarized undulators. Undulators known as elliptically polarized undulators have an adjustable field direction. Some other undulators have a magnetic field direction that rotates. These are known as helical undulators.
The typical undulator consists of a massive C-shaped frame, two or four magnet arrays, and one or more driving mechanisms. Magnet arrays attached to the frame and driving mechanisms provide precise arrays motion, i.e. variation of the gap between them. Because forces between magnet arrays are quite significant (few tons) and varying, and the tolerances on magnet array position are quite small (few microns), the C-frame must be very stiff. These requirements require large and heavy structures for the magnet arrays holding. Furthermore, undulators are typically very expensive.
What is needed is a compact sized undulator that reduces weight, complexity, and cost and that provides mechanical integrity without compromising magnetic field control and quality. The present invention satisfies this need.